One of the St. Louis Cardinals' top pitching prospects, left-hander Quinn Mathews, is headed to the majors. Mathews, St. Louis' No. 7 prospect for 2026 on MLB Pipeline, is scheduled to make his MLB debut this weekend, Cardinals manager Oliver Marmol told reporters, including MLB.com's Brenden Schaeffer, on Thursday. While the roster move hasn't been made official yet, the 25-year-old is expected to toe the slab in the big leagues for the first time on Saturday against the Toronto Blue Jays. The Cardinals are currently in a stretch of playing 20 consecutive games to start the second half of the season. So, calling up Mathews should give some of St. Louis' other arms a little extra rest during a daunting part of the team's schedule. But if the southpaw pitches the way he has in the minors this year, he could wind up sticking around in the big leagues and contributing to the Cardinals' late-season playoff push. What should Cardinals fans expect from Quinn Mathews in his MLB debut? Feb 12, 2025; Jupiter, FL, USA; St. Louis Cardinals pitcher Quinn Mathews throws during Spring Training. Mandatory Credit: Jim Rassol-Imagn Images | USA TODAY Sports via Reuters ConnectSo far in 2026, Mathews has posted a 3.13 ERA in 19 starts with the Triple-A Memphis Redbirds. The 25-year-old has also racked up 111 strikeouts in 92 innings this year. Most notably, though, the 2023 fourth-round draft pick has a 1.04 ERA in four Triple-A starts this month. That builds on the left-hander's strong month of June, when he had a 2.05 ERA in five games. St. Louis finds itself three games back of a National League Wild Card spot right now. At 54-55, it remains to be seen what the Cardinals' approach to the trade deadline will be. Depending on what moves the franchise makes, a spot in St. Louis' rotation might open up over the next few days. And depending on how Mathews pitches in his first MLB start, the young hurler could earn a long-term role with the big league club. The Cardinals have another top prospect, outfielder Joshua Báez, who's knocking on the door of the majors. The 23-year-old has launched 32 home runs in 92 Triple-A games this year. While St. Louis fans will seemingly have to wait a bit longer for the righty-swinging slugger to arrive in the big leagues, they can at least look forward to Mathews' MLB debut this weekend. Add us as a preferred source on GoogleFollow